public class Test {
    public static void main(String[] args) {
        String s="hello world";
        System.out.println(s.substring(1));//从1下标开始截取
        System.out.println(s.substring(1,3));//左闭右开截取
        String s1="  ha ha ha ha ah  ";
        System.out.println(s1.trim());
    }
}
